else if(event.getSource()==exitItem);
      {
        if(saveBoolean==true)
        {
          int E =JOptionPane.showConfirmDialog(textArea,"是否保存已修改文件","提示",JOptionPane.YES_NO_CANCEL_OPTION);
          switch(E)
          {
          case JOptionPane.YES_OPTION:
            this.saveFile();
          case JOptionPane.NO_OPTION:
            System.exit(0);
          }
        }
        else
        {
          System.exit(0);
        }
      }